Tobacco smoke filter

ABSTRACT

A tobacco smoke filter a copper-containing porphyrin or an iron analog of C.I. Reactive Blue 21 dye. A method of making a first tobacco smoke filter segment, comprising the steps of, first, providing one or more than one substance; producing a mixture of cellulose fiber and the substance; heating the mixture for a sufficient time at one or more than one temperature sufficient to covalently link the substance to the cellulose fiber; and forming the cellulose fiber with covalently bound substance into the first tobacco smoke filter segment. The substance can be a copper-containing porphyrin or an iron analog of C.I. Reactive Blue 21 dye.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from International Patent Application371 of PCT/US01/41997, entitled “Tobacco Smoke Filter”, filed Sep. 4,2001, which is a Divisional of U.S. Provisional Patent Application60/232,048, entitled “Cigarette Filter”, filed Sep. 12, 2000; thecontents of which are incorporated by reference herein in its entirety.

BACKGROUND

It is widely known that tobacco smoke contains mutagenic andcarcinogenic compounds which cause substantial morbidity and mortalityto smokers. Examples of such substances include polycyclic aromatichydrocarbons (PAH) and nitrosamines.

Polycyclic aromatic hydrocarbons appear to cause toxicity byintercalating within DNA molecules. Nitrosamines are electrophilic,alkylating agents which are potent carcinogens. Nitrosamines are notpresent in fresh or green tobaccos and are not formed during combustion.They are instead formed by reactions involving free nitrate duringprocessing and storage of tobacco, or by the post-inhalation, metabolicactivation of secondary amines present in tobacco smoke.

Attempts to reduce the amount of toxic and mutagenic compounds thatreach the smoker include tobacco smoke filters positioned between theburning tobacco and the smoker.

Conventional filters are made of cellulose acetate, with or withoutactivated charcoal. These conventional filters, however, are onlypartially effective in reducing the amount of toxic and mutageniccompounds reaching the smoker. Further, conventional filtersdisadvantageously remove flavor compounds, thereby decreasing acceptanceby the smoker.

There is, therefore, a need for an improved filter for a smokable devicethat substantially removes toxic and mutagenic compounds from tobaccosmoke. Further, there is a need for an improved filter which allows thepassage of flavor compounds while substantially removing toxic andmutagenic compounds from tobacco smoke. Such an improved filter wouldpreferably be simple and inexpensive to manufacture, and convenient touse.

SUMMARY

The present invention is directed to a tobacco smoke filter that meetsthese needs. In one embodiment, there is provided a method of making afirst tobacco smoke filter segment. The method comprises the steps of,first, providing one or more than one copper-containing porphyrin. Then,a mixture of cellulose fiber and the copper-containing porphyrin isproduced. Next, the mixture is heated for a sufficient time at one ormore than one temperature sufficient to covalently link thecopper-containing porphyrin to the cellulose fiber. Then, the cellulosefiber with covalently bound, copper-containing porphyrin is formed intothe first tobacco smoke filter segment.

In one embodiment, the copper-containing porphyrin provided is a copperphthalocyanine. In a preferred embodiment, the copper-containingporphyrin provided is C.I. Reactive Blue 21 dye. In another embodiment,the mixture of cellulose fiber and the copper-containing porphyrinproduced comprises a ratio of about 1.2:10 copper-containing porphyrinto cellulose fiber by weight. In a preferred embodiment, the mixture ofcellulose fiber and the copper-containing porphyrin further comprisessodium sulfate and chlorine water.

In one embodiment, The method further comprises rinsing the mixture ofcellulose fiber with covalently bound, copper-containing porphyrin afterheating the mixture. In another embodiment, the method furthercomprising adding one or more than one additional substance to thecellulose fiber with covalently bound, copper-containing porphyrin. Inone embodiment, the one or more than one additional substance isselected from the group consisting of activated charcoal, chitin andlignin. In another embodiment, the one or more than one additionalsubstance is selected from the group consisting of an antioxidant, drywater, a humectant, microcapsules, a radical scavenger, a surfactant andcombinations of the preceding.

According to one embodiment, there is provided a method of making asmokable device. The method comprises the steps of, first, providing afirst tobacco smoke filter segment made according to the presentinvention, and then affixing the first tobacco smoke filter segment to abody of divided tobacco. The method can further comprise the step ofaffixing a second tobacco smoke filter segment that is substantiallyfree of copper-containing porphyrin to the body of divided tobacco. In apreferred embodiment, the second tobacco smoke filter segment affixed tothe body of divided tobacco comprises cellulose acetate fibers treatedwith triacetin.

According to one embodiment of the present invention, there is provideda tobacco smoke filter comprising a first tobacco smoke filter segmentmade according to the present invention. The tobacco smoke filter canalso comprise a second tobacco smoke filter segment that issubstantially free of copper-containing porphyrin. According to anotherembodiment, there is provided a smokable device comprising the tobaccosmoke filter according to the present invention affixed to a body ofdivided tobacco.

According to one embodiment of the present invention, there is provideda method of filtering tobacco smoke. The method comprises the steps ofproviding the smokable device of according to the present invention,igniting the body of divided tobacco such that smoke passes through thebody of divided tobacco and into the filter, and allowing the smoke topass through the filter thereby filtering the smoke.

The present invention further comprises an iron analog of C.I. ReactiveBlue 21 dye and methods, tobacco smoke filters and smokable devices ofthe present invention, where the iron analog of C.I. Reactive Blue 21dye is substituted for the copper-containing porphyrin. Additionally,there is provided.

DESCRIPTION

According to one embodiment of the present invention, there is provideda filter for tobacco smoke. The filter can be provided in combinationwith cigarettes or cigars or other smokable devices containing dividedtobacco. Preferably, the filter is secured to one end of the smokabledevice, positioned such that smoke produced from the tobacco passes intothe filter before entering the smoker. The filter can also be providedby itself, in a form suitable for attachment to a cigarette, cigar,pipe, or other smokable device.

The filter according to the present invention advantageously removes asignificant proportion of mutagens and carcinogens from cigarette smoke.The filter further retains satisfactory or improved smoke flavor,nicotine content, and draw characteristics. The filter is designed to beacceptable to the user, being neither cumbersome nor unattractive as arecommercially made filters which are designed to add onto the ends ofpremade cigarettes. Further, filters according to the present inventioncan be made of inexpensive, safe and effective components, and can bemanufactured with only minor modifications of standard cigarettemanufacturing machinery.

According to one embodiment of the present invention, the filtercomprises a porous substrate. The porous substrate can be any nontoxicmaterial suitable for use in filters for smokable devices that are alsosuitable for incorporation with the other substances according toembodiments of the present invention. Such porous substrates includecellulosic fiber such as cellulose acetate, cotton, wood pulp, andpaper; and polyesters, polyolefins, ion exchange materials and othermaterials as will be understood by those with skill in the art withreference to this disclosure.

Filter Containing a Humectant

According to one embodiment of the present invention, the filtercomprises at least one humectant, with or without other substancesdisclosed in this disclosure. The humectant is capable of absorbingmoisture from tobacco smoke and releasing it into the porous substratein order to wet-filter tobacco smoke that passes through the filter.Among other advantages, wet-filtration systems according to the presentinvention help remove particulate matter from tobacco smoke and can bemade integral with a tobacco containing product.

The humectant can be any suitable humectant. For example, the humectantcan be selected from the group consisting of glycerol, sorbitol,propylene glycol, sodium lactate, calcium chloride, potassium phosphate,sodium pyrophosphate or sodium polyphosphate, calcium citrate, calciumgluconate, potassium citrate, potassium gluconate, sodium tartrate,sodium potassium tartrate, and sodium glutamate.

In a preferred embodiment, the humectant incorporated into the filter issodium pyroglutamate (also known as sodium 2-pyrrolidone-5-carboxylateor NaPCA). Advantageously, sodium pyroglutamate is nontoxic, effectiveat removing charged particles from tobacco smoke and functions as ahumectant in the temperature range of tobacco smoke. Further, it isnonhazardous, stable, simple to manufacture and convenient to use.Sodium pyroglutamate has the following structure:

Filters according to the present invention are simple and inexpensive tomanufacture. In one method of manufacture, a solution containing thehumectant, such as sodium pyroglutamate, is prepared. Then, the poroussubstrate is wetted with the solution. The wetted substrate is thendried, leaving a residue of the humectant dispersed on or in the poroussubstrate. In a preferred embodiment, the humectant is present in anamount of from about 5% to about 60% by dry weight of the filter.

The effectiveness of a tobacco smoke filter containing sodiumpyroglutamate according to the present invention was tested as follows.

Three types of filters were tested for relative effectiveness inremoving tar from cigarette smoke:

1) Conventional cellulose acetate filter (“Cell-Ac”);

2) Wet-filtration tobacco smoke filter containing cellulose acetate withsodium pyroglutamate (“SoPyro”) according to the present invention; and

3) Commercially available wet-filtration tobacco smoke filter(Aquafilter®, Aquafilter Corp.).

Cellulose acetate filters containing sodium pyroglutamate were preparedby, first, removing cellulosic filters from commercial cigarettes. Thefibers weighed approximately 0.21 g. Next, approximately 0.5 mL of a 10%by weight solution of sodium pyroglutamate was applied to each filter,and the filter was dried overnight at 60° C.

The conventional cellulose acetate filter and the cellulose acetatefilters containing sodium pyroglutamate were weighed and inserted into a40 mm segment of polycarbonate tubing having an inside diameteridentical to the outside diameter of a standard cigarette. A filterlesscigarette having 0.85 g of tobacco was inserted into one end of thepolycarbonate tubing in proximity to one end of the filter. The otherend of the polycarbonate tubing was attached to tubing connected to asuction pump. Duplicates of each filter type were tested. EachAquafilter® used in this test was also attached to a filterlesscigarette having 0.85 g of tobacco and then attached to tubing connectedto a suction pump.

The filtered cigarettes were lit and intermittent suction, simulatinginhalation of cigarette smoke, was applied until the cigarette hadburned to within 12.5 mm of the unlit end. The filters were removed fromeither the polycarbonate tube or were removed from the Aquafilter®,weighed, and placed in 10 mL of methanol to elute tar and othersubstances from the smoke that were retained in the filter. Lightabsorbance (at a wavelength of 350 nm) of the ethanolic filter eluateswas used as an index of the amount of smoke components retained on thefilters. The weight gained by the filters during smoke passage was alsorecorded. The results of the test are presented in Table 1.

TABLE 1 TEST FILTER ABSORBANCE at 350 nm Weight Gain 1 Cell-Ac 0.470A.U. 35 mg 2 Cell-Ac 0.381 A.U. 30 mg 3 SoPyro 0.731 A.U. 71 mg 4 SoPyro0.625 A.U. 60 mg 5 Aquafilter ® 0.540 A.U. * 6 Aquafilter ® 0.560 A.U. **The weight gain due to absorbance of smoke components on the Aquafiltercould not be determined, since the Aquafilter actually lost weightduring passage of smoke, presumably due to evaporation of water.

Based on the absorbance data, the filters according to one embodiment ofthe present invention (Tests 3 and 4) are significantly more effectivethan conventional cellulose acetate filters without the humectant (Tests1 and 2), and also more effective than the Aquafilter® (Tests 5 and 6).

Filter Containing Dry Water

According to another embodiment of the present invention, there isprovided a filter for wet-filtering tobacco smoke comprising “drywater,” with or without other substances disclosed in this disclosure.Dry water is a combination of methylated silica and water. In oneembodiment, the methylated silica is present in an amount from about 5%to 40% and the water is present in an amount from about 60%to 95% byweight. In a preferred embodiment, the methylated silica is present inan amount of about 10% and the water is present in an amount of about90% by weight. Advantageously, dry water has good stability when used ina filter according to the present invention. Further, it is inexpensive,nontoxic and not harmful to the environment.

In a preferred embodiment, dry water is present in an amount of about 1%to about 20% by weight of the filter. In a particularly preferredembodiment, dry water is present in an amount of about 5% to about 10%by weight of the filter.

Dry water for use with the present invention can be made, for example,by shaking excess water with methylated silica in a closed containeruntil an equilibrium emulsion is achieved. Excess water is decanted, anda drying agent, such as non-derivatized silica, is added in amountsequivalent to 10% of the amount of methylated silica in the emulsion.The emulsion is further shaken to disperse the drying agent.

One problem associated with the use of dry water in a tobacco smokefilter is that, when present as a continuous layer between the tobaccoand the smoker, dry water tends to clog pores in the filter, therebyincreasing resistance to airflow and decreasing smoking pleasure. Inorder to overcome this problem, there is provided an embodiment of thepresent invention having dry water admixed with a loose fibrousmaterial. This additional fibrous material provides scaffolding toreduce impaction of silica particles into the filter material whensuction is applied by the smoker. Examples of such material includecellulose or cellulose acetate having fiber lengths short enough suchthat the dry water behaves as a flowable powder. In a preferredembodiment, the fiber length is less than about 1 nm. In a preferredembodiment, the tobacco smoke filter according to the present inventionincludes both a porphyrin, as discussed in this disclosure, in additionto the dry water. For example, a tobacco smoke filter according to thepresent invention includes a section of between about 3 mm and 6 mmfilled with dry water, chlorophyllin and cellulose, within the filter orat the distal end of the filter between the conventional filter materialand the tobacco. Tobacco smoke in such a filter passes through the drywater and porphyrin which retain carcinogenic smoke constituents withinthe dry water and chlorophyllin layer.

Tobacco smoke filters according to this aspect of the present inventioncan be made by adding a dry water and porphyrin mixture duringmanufacture of the filter or can be made by injecting the mixture intothe filter or at the interface between the tobacco and the conventionalfilter. The dry water and porphyrin mixture can be injected either intothe axial end of the filter or through the side of the smokable device,such as through a cannula attached to an injection device. Preferably,the injection device meters the amount of material administered per eachinjection.

Alternately, the dry water and porphyrin mixture can be included in afilter extension for attachment to a conventional smokable device suchas a standard cigarette, or to a cigarette filter by the smoker. Thefilter extension comprises a layer of dry water and porphyrin and,preferably, a fibrous material as a matrix. The filter extension furthercomprises a sleeve which extends axially forward for fitting over theproximal end of the smokable device. The sleeve is bounded by a porousretaining element to maintain the dry water and porphyrin within thefilter extension. Preferably, the sleeve further comprises a length ofconventional filter material such that, upon connection to the smokabledevice, the filter extension and smokable device appear to substantiallybe a conventional smokable device.

Filters Containing a Copper-Containing Porphyrin

According to another embodiment of the present invention, there isprovided a cigarette filter comprising at least one porphyrin, such aschlorophyll, with or without other substances disclosed in thisdisclosure. Preferably, the porphyrin is a copper-containing porphyrin,such as chlorophyllin and copper phthalocyanine trisulfonate (copperphthalocyanine, copper phthalocyanate).

Porphyrins are planar compounds which inactivate several classes ofmutagens and carcinogens. Porphyrins inactivate planar mutagens andcarcinogens primarily by binding the carcinogen to the planar porphyrinstructure through hydrophobic interactions. Therefore, porphyrinsideally need to be maintained in aqueous environments to optimallyadsorb these tobacco smoke carcinogens. Porphyrins further inactivatecarcinogens by binding polycyclic aromatic hydrocarbons (PAH) throughπ—π (pi—pi) bonding. The copper-containing porphyrins also inactivatemany classes of non-planar mutagens and carcinogens including somenitrosamines through reaction with the copper ion. While known toinactivate various carcinogens, it has not been known how to effectivelyutilize porphyrins in tobacco smoke filters.

Chlorophyllin is a naturally occurring, copper-containing porphyrin andis the stable form of chlorophyll in which the magnesium present inchlorophyll has been replaced by copper. Chlorophyllin has the followingformula:

Chlorophyllin, however, is difficult to chemically link to tobacco smokefilter components. Therefore, in a preferred embodiment, thecopper-containing porphyrin incorporated into the tobacco smoke filteris copper phthalocyanine. Copper phthalocyanine is a nontoxic, syntheticchlorophyllin analog which can be more easily linked to tobacco smokefilter components than chlorophyllin. Copper phthalocyanine has thefollowing formula:

In one embodiment, the copper-containing porphyrin, such as copperphthalocyanine, is incorporated into a tobacco smoke filter by directlyadding the copper-containing porphyrin to the tobacco smoke filter. In apreferred embodiment, the copper phthalocyanine can be incorporated intoa tobacco smoke filter as a covalently bound ligand to cotton, such asthe textile dye “blue cotton,” or as a covalently bound ligand to rayon,such as “blue rayon,” or as a covalently bound ligand to other suitablematerial as will be understood by those in the art with reference tothis disclosure. In another preferred embodiment, copper phthalocyaninecan be incorporated into a tobacco smoke filter in combination withother tobacco smoke filter embodiments of the present invention.

Copper-containing porphyrin is preferably attached to cellulosic fibersin the form of an activated reagent called C.I. Reactive Blue 21 dye, avinylsulfone derivative of copper phthalocyanine trisulfonate, asdescribed in Hayatsu, Journal of Chromatography, 597:37-56 (1992),incorporated in this disclosure by reference in its entirety, whichforms a stable ether linkage to free hydroxyl groups on cellulosicfibers to form “blue cellulose” or other materials under mild conditions(unlike chlorophyllin).

Cellulose is the base material used to manufacture tobacco smokefilters. The standard form of cellulose used for manufacturing tobaccosmoke filters is cellulose acetate fibers, made by treating cellulosewith acetic anhydride. This reaction replaces the free hydroxyl groupspresent on natural cellulose with more hydrophobic acetate groups. Thecellulose acetate is then treated with triacetin (glycerol triacetate),a solvent that joins some of the cellulose acetate fibers togetherbecause cellulose acetate, unlike cellulose is partially soluble intriacetin. Disadvantageously, however, replacing the hydroxyl groupswith acetate groups and treating the cellulose with triacetin greatlydiminishes the number of potential attachment sites forcopper-containing porphyrin molecules and renders triacetintreated-cellulose acetate less desirable as a base material for tobaccosmoke filters that untreated cellulose.

Therefore, according to one embodiment of the present invention, thereis provided a tobacco smoke filter comprising one or more than onesegment, that is, at least a first segment. The first segment comprisescopper-containing porphyrin and cellulose that has not been treated withacetic anhydride or triacetin. Preferably, the tobacco smoke filterfurther comprises a second segment that comprises cellulose acetatetreated with triacetin but that is substantially free ofcopper-containing porphyrin.

In a preferred embodiment, the copper-containing porphyrin in the firstsegment is present in an amount of from about 0.1% to about 5% by dryweight of the filter covalently bound. In a particularly preferredembodiment, the copper-containing porphyrin in the first segment ispresent in an amount of from about 1% to about 3% by dry weight of thefilter.

In one embodiment of the present invention, there is provided a smokabledevice comprising a body of divided tobacco affixed to a tobacco smokefilter comprising the first segment. Preferably, the smokable devicecomprises the first segment adjacent the body of divided tobacco and asecond segment adjacent that is at the proximal end of the smokabledevice. This configuration advantageously allows a user of the smokabledevice to draw smoke directly through the second segment of the tobaccosmoke filter, thereby obtaining a convention feel while using thesmokable device.

In another embodiment of the present invention, there is provided amethod of making a tobacco smoke filter as disclosed in this disclosure.The method produces a tobacco smoke filter comprising copper-containingporphyrin, such as copper phthalocyanine, that tends to stay uniformlydispersed in the filter during the manufacturing process and as moistureaccumulates in the filter during the burning of the tobacco, and thattends not to leach out of the filter during use.

The method comprises preparing the filter material from cellulose orfrom other materials to which one or more than one copper-containingporphyrin has been covalently bound. The filter material is Fen madeinto tobacco smoke filters comprising at least one segment of thematerial with covalently bound, copper-containing porphyrin. The tobaccosmoke filter can also comprise one or more than one segment of materialthat is substantially free of copper-containing porphyrin. The use offilter material comprising covalently bound, copper-containing porphyrinpermits high speed, high-volume manufacturing of smokable devices, suchas cigarettes, incorporating a filter according to the present inventionusing existing equipment.

The method comprises the steps of, first providing one or more than onecopper-containing porphyrin, such as copper phthalocyanine. In apreferred embodiment, the copper-containing porphyrin is a vinylsulfonederivative of copper phthalocyanine trisulfonate, such as C.I. ReactiveBlue 21 dye (ORCO® REACTIVE Turquoise RP, available from OrganicDyestuffs Corporation, East Providence, RI US).

The amounts of material given in the following steps are relativeamounts and are for example, only. The amounts would be scaled upwardfor commercial production as will be understood by those in the art withreference to this disclosure. After providing the copper-containingporphyrin, a mixture is produced comprising a ratio of about 1.2:10copper-containing porphyrin to cellulose fiber by weight, such asapproximately 1.2 g of the copper-containing porphyrin and approximately10 g of cellulose fiber of a grade suitable for use as paper-makingpulp. The mixture further comprises approximately 10 g of sodium sulfatein approximately 200 mL of chlorine water. Then, the mixture is heatedto about 30° C. for about 35 minutes, after which, the temperature israised to about 70° C. for about 60 minutes to complete the covalentbinding of the copper-containing porphyrin to the cellulose fiber. Themixture is then collected on a mesh and rinsed thoroughly under runningtap water, producing cellulose fiber with covalently bound,copper-containing porphyrin. The cellulose fiber with covalently bound,copper-containing porphyrin is then formed into a segment of a tobaccosmoke filter using commercially available equipment. The filter is thenattached to a body of divided tobacco to produce a smokable deviceaccording to the present invention. Additionally, the present inventioncomprises copper-containing porphyrin impregnated paper made asdisclosed above, for use in making tobacco smoke filters or for otheruses.

The method of method of making a tobacco smoke filter can furthercomprise adding one or more than one additional substance to the tobaccosmoke filter of the present invention in addition to copper-containingporphyrin. In a preferred embodiment, the one or more than oneadditional substance is chitin, a polysaccharide derived from the shellsof arthropods, because chitin particles comprise a high density of freehydroxyl groups that can be covalently attached to metal-porphyrincompounds, such as C.I. Reactive Blue 21 dye. By dry weight, chitin canbe covalently bound to about four times as much C.I. Reactive Blue 21dye as an equivalent amount of cellulose. In a preferred embodiment,chitin granules (available from Sigma Chemical Company, St. Louis, Mo.US) are covalently bound to copper-containing porphyrin in methodequivalent to the reaction disclosed above in which the cellulose isreplaced with chitin. The amounts of material given in the followingsteps are relative amounts and are for example, only. The amounts wouldbe scaled upward for commercial production as will be understood bythose in the art with reference to this disclosure. This can beaccomplished by, for example, dissolving 0.8 g C.I. Reactive Blue 21 dyeand 6.8 g sodium sulfate in 133 mL of distilled water. Then, 2.0 g ofchitin are added and the mixture is stirred gently for 20 minutes at 30°C. Next, 2.7 g of sodium carbonate are added and the mixture is allowedto stand at 30° C. for 15 minutes and is then heated from 30° C. to 70°C. over the course of 20 minutes. The mixture is then stirred whilemaintaining a temperature of 70° C. for 60 minutes, to allow the linkingreaction to go to completion. The resulting copperphthalocyanine-derivatized chitin is collected in a sintered glassfilter and rinsed thoroughly with distilled water to remove unreacteddye and the salts.

The copper-containing porphyrin covalently bound to chitin can beincorporated into paper by mixing it with cellulose pulp in a ratio ofbetween about 1:20 and about 1:1 copper-containing porphyrin covalentlybound to chitin to cellulose by dry weight. The cellulose can alsocomprise covalently bound copper-containing porphyrin according to thepresent invention. The incorporation comprises mixing the chitin withcellulose pulp in the initial step of paper making, as the cellulose isbeing macerated in water (before the pulp is laid out on a mesh, pressedand dried). The chitin-impregnated cellulose can then be used formanufacture of tobacco smoke filters according to the present invention.

In a preferred embodiment, the one or more than one additional substanceis activated charcoal or is lignin (a constituent of wood produced as abyproduct of preparation of cellulose paper pulp from wood). Either orboth of these substances can be added to cellulose covalently bound tocopper-containing porphyrin according to the present invention,especially for fabrication of paper incorporating activated charcoal orlignin . When present, activated charcoal or lignin is added to thecellulose in the same manner and ratio as chitin disclosed above.

Further, in a preferred embodiment the filter produced as disclosedabove is attached to a tobacco smoke filter made of standard celluloseacetate fibers treated with triacetin to produce a filter comprising atleast two segments. Preferably, the segment comprising cellulose acetatefibers treated with triacetin is proximal, that is away from the lit endof the smokable device, to the segment comprising copper-containingporphyrin impregnated cellulose fibers, and the segment comprisingcopper-containing porphyrin impregnated cellulose fibers is between thebody of divided tobacco and the segment comprising cellulose acetatefibers treated with triacetin.

The effectiveness of a two segment filter made according to the presentinvention was tested as follows. Tobacco smoke filter were preparedcomprising two segments. Each proximal segment comprised celluloseacetate fibers treated with triacetin. The distal segment of one filtercomprised copper phthalocyanine impregnated cellulose fibers asdisclosed above, while the distal segment of the other filter comprisedcellulose fibers that were not treated with triacetin and that were notimpregnated with a copper-containing porphyrin. The two segment filterswere then placed in plastic tubing leaving approximately 0.5 cm of thetube without the filter, and a 3 cm long rod of tobacco from a Marlboro®cigarette was fitted into the 0.5 cm empty end of the tubing abuttingthe filter to create smokable devices. The tobacco was lit and thesmokable devices were subjected to ten 20 mL puffs with a suction pump,until the tobacco was burned down flush with the end of the plastictube. The filters were removed from the tubes and placed in 10 mL ofmethanol containing ammonia in a 50:1 dilution to elute the retainedpolycyclic aromatic hydrocarbons from the filters. The 10 mL extractswere evaporated down to 1 mL and subjected to thin layer chromatographyon aluminum oxide with 5 mL hexane. Total polycyclic aromatichydrocarbon content was estimated spectrofluorimeterically. The resultsindicated that the two segment filter comprising copper phthalocyanineaccording to the present invention retained 80 ng of polycyclic aromatichydrocarbons while the two segment filter without copper phthalocyanineretained 6 ng of polycyclic aromatic hydrocarbons. This 13-fold increaseis particularly significant in that the total polycyclic aromatichydrocarbons produced during combustion of the tobacco rod is estimatedto be between about 100 ng and 200 ng. Therefore, the two segment filteraccording to the present invention removed between about 40% and 80% ofthe total amount of polycyclic aromatic hydrocarbons from the tobaccosmoke.

In another embodiment, the tobacco smoke filter of the present inventioncomprises an iron analog of the copper-containing porphyrin rather thanthe copper-containing porphyrin. In a preferred embodiment, the analogis an iron analog of C.I. Reactive Blue 21 dye produced by acidificationof the C.I. Reactive Blue 21 dye, addition of iron sulfate and thenaddition of a suitable base, as will be understood by those in the artwith reference to this disclosure. Alternately, an iron salt, such asanhydrous iron chloride, can be used instead of a copper salt duringinitial synthesis of C.I. Reactive Blue 21 dye to produce an ironanalog.

The iron analog of C.I. Reactive Blue 21 dye can also be used to makepaper impregnated with iron analog of C.I. Reactive Blue 21 dye,corresponding to the copper-containing porphyrin impregnated paper asdisclosed above, for use in making tobacco smoke filters or for otheruses.

Filter Containing Microcapsules

According to another embodiment of the present invention, there isprovided a filter for tobacco smoke comprising a porous substrate havingmicrocapsules dispersed in the porous substrate, with or without othersubstances disclosed in this disclosure. The microcapsulespreferentially include an inner core with an outer shell.

The cores of the microcapsules comprise at least one vegetable oil.Suitable vegetable oils include at least one oil selected from the groupconsisting of castor oil, cotton seed oil, corn oil, sunflower oil,sesame oil, soybean oil, and rape oil. In a preferred embodiment, thevegetable oil is safflower oil. Other oils are also suitable, as will beunderstood by those with skill in the art with reference to thisdisclosure. In a preferred embodiment, the vegetable oil is present inan amount of from about 20% to about 80% by dry weight of themicrocapsules, and more preferably from about 30% to about 70% by dryweight of the microcapsules.

In a preferred embodiment, the microcapsule cores also contain aporphyrin, such as chlorophyllin, or another porphyrin such copperphthalocyanine. When present, the chlorophyllin is preferably present inan amount of from about 1% to about 10% by dry weight of themicrocapsules, and more preferably from about 2% to about 5% by dryweight of the microcapsules.

In a preferred embodiment, the microcapsule shells comprise a humectant.In a preferred embodiment, the humectant is sodium pyroglutamate, thoughother humectants can be used as will be understood by those with skillin the art with reference to this disclosure. In a preferred embodiment,the humectant, such as sodium pyroglutamate, is present in an amount offrom about 10% to about 90% by dry weight of the microcapsules, and morepreferably from about 20% to about 70% by dry weight of themicrocapsules.

In another preferred embodiment, the microcapsule shells also comprisemethylcellulose. In a preferred embodiment, the methylcellulose ispresent in an amount of from about 5% to about 30% by dry weight of themicrocapsules, and more preferably from about 10% to about 25% by dryweight of the microcapsules.

In another preferred embodiment, the microcapsule shells comprises apolymeric agent such as polyvinylalcohol or polyvinyl pyrrolidone, orcan comprise both polyvinylalcohol and polyvinyl pyrrolidone, inaddition to methylcellulose or in place of methylcellulose. In apreferred embodiment, the polymeric agent is present in an amount offrom about 2% to about 30% by dry weight of the microcapsules, and morepreferably from about 5% to about 20% by dry weight of themicrocapsules.

Compounds used in formulation of microcapsules according to the presentinvention are available from a variety of sources known to those withskill in the art, such as Sigma Chemical Co., St. Louis, Mo. US.

Microcapsules suitable for use in the present invention can be madeaccording to a variety of methods known to those with skill in the art.For example, microcapsules according to the present invention can beproduced by combining 200 g of vegetable oil with 500 g of an aqueoussuspension comprising 25 g of low-viscosity methylcellulose, 5 g ofchlorophyllin, 50 g of sodium pyroglutamate and 150 g of corn starch inwater. The mixture is emulsified and spray-dried to form microcapsules.

Microcapsules according to the present invention can be formed by spraydrying methods at the site-of cigarette manufacturing machinery byspraying onto sheets of cellulose acetate filter tow before the tow isformed into cylindrical filters. Alternatively, suitable microcapsulescan be premanufactured and added to sheets of cellulose acetate filtertow by dropping the microcapsules onto the tow with a vibrating pan orby other techniques as will be understood by those with skill in the artwith reference to this disclosure. Further, microcapsules can beincorporated into prefabricated filters by sprinkling the microcapsulesinto the filter tow before the tow is rolled and shaped in rods offilter material.

As will be appreciated by those with skill in the art, the manufactureof filters containing microcapsules according to the present inventionwill require only minor modification of conventional filter-cigarettemanufacturing equipment. Further, the manufacture of filters containingmicrocapsules according to the present invention is only marginally moreexpensive than conventional filters.

In use, the humectant portions of the microcapsules trap moisture fromtobacco smoke passing through the filter. Sodium pyroglutamate isparticularly preferred because it can be incorporated into the filter ina dry form.

When present, the oil portions of the microcapsules trap certain harmfulvolatile compounds like pyridine without impeding the flow of flavor andaroma producing compounds. When present, chlorophyllin is a potentinactivator of carcinogenic components of tobacco smoke.

The methylcellulose portions of the microcapsules impart structuralstability to the microcapsules but disperse upon warming and whenexposed to moisture. Unlike most commonly used viscosity-impartingsubstances, methylcellulose precipitates from warm solutions. Further,it is soluble at lower temperatures than most commonly usedviscosity-imparting substances.

When tobacco smoke filters containing microcapsules comprising a shellof sodium pyroglutamate and methylcellulose and a core of vegetable oiland chlorophyllin, according to the present invention, filter tobaccosmoke, the microcapsules capture heat and moisture from the tobaccosmoke. The methylcellulose precipitates into a fibrous material whichincreases the effective surface area available for wet-filtration of thetobacco smoke. This allows the moisture retained by the sodiumpyroglutamate to rapidly disperse into the filter material. Thechlorophyllin partitions approximately evenly between the aqueous andoil environments, allowing increased inactivation of both particulateand vapor-phase toxic and mutagenic compounds of tobacco smoke than ifthe chlorophyllin was available in only one phase.

Filters Containing a Surfactant

In another preferred embodiment, the filters of the present inventionadditionally comprise at least one surfactant to improve theeffectiveness of the tobacco smoke filter, with or without othersubstances disclosed in this disclosure. In a particularly preferredembodiment, the surfactant is present in an amount of from about 0.1% toabout 10%, and more preferably from about 0.1% to about 2% by weight ofthe filter.

The surfactant is preferably nontoxic and can include one or more of thefollowing classes of compounds: (1) a polyoxyalkylene derivative of asorbitan fatty acid ester (i.e., polyoxyalkylene sorbitan esters), (2) afatty acid monoester of a polyhydroxy-alcohol, or (3) a fatty aciddiester of a polyhydroxy alcohol, though other suitable surfactants willbe understood by those with skill in the art with reference to thedisclosure in this disclosure. Examples of suitable surfactants includeethoxylates, carboxylic acid esters, glycerol esters, polyoxyethyleneesters, anhydrosorbitol esters, ethoxylated anhydrosorbitol esters,ethoxylated natural fats, oils and waxes, glycol esters of fatty acids,polyoxyethylene fatty acid amides, polyalkylene oxide block copolymers,and poly(oxyethylene-consist of-oxypropylene). Other suitablesurfactants can also be used as will be understood by those with skillin the art with reference to the disclosure in this disclosure.

Filters Containing an Additional Substance

The filter can additionally include one or more other substances whichfilter or inactivate toxic or mutagenic components of tobacco smoke.Examples of such substances include antioxidant and radical scavengerssuch as glutathione, cysteine, N-acetylcysteine, mesna, ascorbate, andN,N′-diphenyl-p-phenyldiamine; aldehyde inactivators such as ene-diolcompounds, amines, and aminothiols; nitrosamine traps and carcinogeninactivators such as ion-exchange resins, chlorophyll; and nicotinetraps such as tannic acid and other organic acids. In one preferredembodiment, the filter includes colloidal silica, a compound which canscavenge secondary amines from tobacco smoke, thereby preventingconversion of the secondary amines to nitrosamines in the body. Othersuitable substances can also be used as will be understood by those withskill in the art with reference to the disclosure in this disclosure. Ina preferred embodiment, the other substances are present in an amount offrom about 0. 1 to about 10%, and more preferably from about 0.1 toabout 2% by weight of the filter.

Filters Having Certain Combinations of Substances Disclosed in thisDisclosure

According to another embodiment of the present invention, there isprovided a tobacco smoke filter comprising combinations of substancesdisclosed in this disclosure. In a preferred embodiment, the filtercomprises a humectant, such as sodium pyroglutamate, in combination withdry water. This combination functions synergistically to improvewet-filtration of tobacco smoke. In one embodiment, the filter comprisessodium pyroglutamate in an amount of between about 1% and 20% of theaqueous portion of the dry water by weight. In a preferred embodiment,the filter comprises sodium pyroglutamate in an amount of between about5% and 10% of the aqueous portion of the dry water by weight.

In another preferred embodiment, the filter comprises acopper-containing porphyrin, such as copper phthalocyanine, incombination with a humectant such as sodium pyroglutamate, dry water orboth. These combinations are particularly preferred becausecopper-containing porphyrins scavenge carcinogens better in aqueousenvironments. In one embodiment, the copper-containing porphyrincomprises between about 0.5% to about 5% of the dry water by weight.

In another preferred embodiment, the filter comprises chlorophyllin, incombination with a humectant, dry water or both. In one embodiment, thechlorophyllin comprises between about 0.5% to about 5% of the dry waterand the humectant is between about 1% and 20% of the dry water byweight.

A specific example of such a combination would be blue rayon (copperphthalocyanine impregnated rayon) combined with dry water. When presentin an amount between about 10 mg to 100 mg in the 3 mm tobacco end of astandard cellulose acetate tobacco smoke filter, the combination doesnot impair draw but reduces mutagenicity of tobacco smoke 75-80% by theAmes test. Further, these components are inexpensive, safe, and notharmful to the environment.

Combinations of dry water and porphyrin are produced, for example, byadding dry porphyrin in amounts up to the amount of methylated silica byweight to dry water, made according the description in this disclosure.The porphyrin must be added after the dry water has been stablyemulsified. Dissolution of porphyrin in water prior to emulsification inmethylated silica results in an unstable porphyrin/dry water compound.In a preferred embodiment, the porphyrin is added in amounts of about0.1 to 0.5 grams per gram of methylated silica. A similar method is usedto produce the combination of dry water and porphyrin-derivatized fiber,such as blue cotton or blue rayon. After combining the two substances,the combination is shaken or stirred to homogeneity.

Filters Having a Circumferential Barrier

Filters according to the present invention are preferably provided withan exterior, circumferential, moisture-impervious barrier or casing toprevent wetting of the smoker's hands. Such a barrier can be made from apolymeric material such as ethylvinyl acetate copolymer, polypropylene,or nylon, as is understood by those with skill in the art.

Position of Substances within Filters

The substances disclosed in this disclosure can be incorporated intofilters according to the present invention in a variety ofconfigurations. For example, the substance or substances can bedispersed throughout the filter in a substantially uniform manner.Alternately, the substance or substances can be dispersed in only onesegment of the filter such as in the proximal third (the end nearest thesmoker), in the middle third or in the distal third (the end nearest thetobacco).

In another embodiment, at least one substance is dispersed in onesegment of the filter and at least one other substance is dispersed in adifferent segment of the filter. The two segments can have overlappingareas. For example, a filter according to the present invention can havedry water dispersed in the distal third of the filter and acopper-containing porphyrin dispersed in the proximal third of thefilter. Also for example, a filter according to the present inventioncan have microcapsules dispersed in the distal half of the filter andsodium pyroglutamate dispersed in the proximal two-thirds of the filter,such that the two substances are dispersed in an overlapping area of thefilter as well as nonoverlapping areas.

In another embodiment, the substance or substances can be incorporatedinto a filter that is then affixed to an end of a standard tobacco smokefilter. In a preferred embodiment, the substance or substances areincorporated into a tobacco smoke filter that resembles a shortenedversion of a standard tobacco smoke filter, and the shortened filter isthen affixed to an end of a standard tobacco smoke filter. In thisembodiment, the user will not be overtly aware of the additionalshortened filter because of its resemblance in construction to astandard filter, unlike commercially available filters which add ontothe proximal end of a smokable device.

Further, the substance or substances according to the present inventioncan be incorporated into a layer of the filter between the fibrousmaterial making up the remainder of the filter, and the body of dividedtobacco.

Smokable Devices Incorporating Filters According to the PresentInvention

According to another embodiment of the present invention, there isprovided a smokable device comprising a tobacco smoke filter asdisclosed in this disclosure affixed to a body of divided tobacco. Forexample, such a smokable device can be a cigarette incorporating afilter containing microcapsules having sodium pyroglutamate dispersed inthe porous substrate.

Method of Filtering Tobacco

According to another embodiment of the present invention, there isprovided a method of filtering tobacco in a smokable device. The methodcomprises the steps of, first, providing a smokable device comprisingthe tobacco smoke filter according to the present invention affixed to abody of divided tobacco. Next, the body of divided tobacco is ignitedsuch that smoke passes through the body and into the filter. Then, thesmoke is allowed to pass through the filter thereby filtering the smoke.

Method of Making a Smokable Device

According to another embodiment of the present invention, there isprovided a method of making a smokable device. The method comprises thesteps of, first, providing a tobacco smoke filter according to thepresent invention. Next, the filter is affixed to a body of dividedtobacco.

Although the present invention has been discussed in considerable detailwith reference to certain preferred embodiments thereof, otherembodiments are possible. Therefore, the spirit and scope of theappended claims should not be limited to the description of thepreferred embodiments contained in this disclosure.

What is claimed is:
 1. A method of making a first tobacco smoke filtersegment, comprising the steps of: (a) providing one or more than onecopper-containing porphyrin; (b) producing a mixture of cellulose fiber,sodium sulfate, chlorine water and the copper-containing porphyrin; (c)heating the mixture for a sufficient time at one or more than onetemperature sufficient to covalently link the copper-containingporphyrin to the cellulose fiber; and (d) forming the cellulose fiberwith covalently bound, copper-containing porphyrin into the firsttobacco smoke filter segment.
 2. The method of claim 1, where thecopper-containing porphyrin provided is a copper phthalocyanine.
 3. Themethod of claim 1, where the copper-containing porphyrin provided isC.I. Reactive Blue 21 dye.
 4. The method of claim 1, where the mixtureof cellulose fiber and the copper-containing porphyrin producedcomprises a ratio of about 1.2:10 copper-containing porphyrin tocellulose fiber by weight.
 5. The method of claim 1, further comprisingrinsing the mixture of cellulose fiber with covalently bound,copper-containing porphyrin after heating the mixture.
 6. The method ofclaim 1, further comprising adding one or more than one additionalsubstance to the cellulose fiber with covalently bound,copper-containing porphyrin.
 7. The method of claim 6, where the one ormore than one additional substance is selected from the group consistingof activated charcoal, chitin and lignin.
 8. The method of claim 6,where the one or more than one additional substance is selected from thegroup consisting of an antioxidant, dry water, a humectant,microcapsules, a radical scavenger, a surfactant and combinations of thepreceding.
 9. A method of making a smokable device comprising the stepsof: (a) providing a first tobacco smoke filter segment made according toclaim 1; and (b) affixing the first tobacco smoke filter segment to abody of divided tobacco.
 10. The method of claim 9, further comprisingthe step of affixing a second tobacco smoke filter segment that issubstantially free of copper-containing porphyrin to the body of dividedtobacco.
 11. The method of claim 10, where the second tobacco smokefilter segment affixed to the body of divided tobacco comprisescellulose acetate fibers treated with triacetin.
 12. A tobacco smokefilter comprising a first tobacco smoke filter segment made according toclaim
 1. 13. A tobacco smoke filter comprising a first tobacco smokefilter segment made according to claim 1, and further comprising asecond tobacco smoke filter segment that is substantially free ofcopper-containing porphyrin.
 14. A smokable device comprising thetobacco smoke filter according to claim 12 affixed to a body of dividedtobacco.
 15. A smokable device comprising the tobacco smoke filteraccording to claim 13 affixed to a body of divided tobacco.
 16. A methodof filtering tobacco smoke comprising the steps of: (a) providing thesmokable device of claim 14; (b) igniting the body of divided tobaccosuch that smoke passes through the body of divided tobacco and into thefilter; and (c) allowing the smoke to pass through the filter therebyfiltering the smoke.
 17. A method of filtering tobacco smoke comprisingthe steps of: (a) providing the smokable device of claim 15; (b)igniting the body of divided tobacco such that smoke passes through thebody of divided tobacco and into the filter; and (c) allowing the smoketo pass through the filter thereby filtering the smoke.
 18. A method ofmaking a first tobacco smoke filter segment, comprising the steps of:(a) providing an iron analog of C.I. Reactive Blue 21 dye; (b) producinga mixture of cellulose fiber and the iron analog of C.I. Reactive Blue21 dye; (c) heating the mixture for a sufficient time at one or morethan one temperature sufficient to covalently link the iron analog ofC.I. Reactive Blue 21 dye to the cellulose fiber; and (d) forming thecellulose fiber with covalently bound iron analog of C.I. Reactive Blue21 dye into the first tobacco smoke filter segment.
 19. The method ofclaim 18, where the mixture of cellulose fiber and the iron analog ofC.I. Reactive Blue 21 dye further comprises sodium sulfate and chlorinewater.
 20. The method of claim 18, further comprising rinsing themixture of cellulose fiber with covalently bound iron analog of C.I.Reactive Blue 21 dye after heating the mixture.
 21. The method of claim18, further comprising adding one or more than one additional substanceto the cellulose fiber with covalently bound, copper-containingporphyrin.
 22. The method of claim 21, where the one or more than oneadditional substance is selected from the group consisting of activatedcharcoal, chitin and lignin.
 23. The method of claim 21, where the oneor more than one additional substance is selected from the groupconsisting of an antioxidant, dry water, a humectant, microcapsules, aradical scavenger, a surfactant and combinations of the preceding.
 24. Amethod of making a smokable device comprising the steps of: (a)providing a first tobacco smoke filter segment made according to claim18; and (b) affixing the first tobacco smoke filter segment to a body ofdivided tobacco.
 25. The method of claim 24, further comprising the stepof affixing a second tobacco smoke filter segment that is substantiallyfree of iron analog of C.I. Reactive Blue 21 dye to the body of dividedtobacco.
 26. The method of claim 25, where the second tobacco smokefilter segment affixed to the body of divided tobacco comprisescellulose acetate fibers treated with triacetin.
 27. A tobacco smokefilter comprising a first tobacco smoke filter segment made according toclaim
 18. 28. A tobacco smoke filter comprising a first tobacco smokefilter segment made according to claim 18, and further comprising asecond tobacco smoke filter segment that is substantially free of ironanalog of C.I. Reactive Blue 21 dye.
 29. A smokable device comprisingthe tobacco smoke filter according to claim 27 affixed to a body ofdivided tobacco.
 30. A smokable device comprising the tobacco smokefilter according to claim 28 affixed to a body of divided tobacco.
 31. Amethod of filtering tobacco smoke comprising the steps of: (a) providingthe smokable device of claim 29; (b) igniting the body of dividedtobacco such that smoke passes through the body of divided tobacco andinto the filter; and (c) allowing the smoke to pass through the filterthereby filtering the smoke.
 32. A method of filtering tobacco smokecomprising the steps of: (a) providing the smokable device of claim 30;(b) igniting the body of divided tobacco such that smoke passes throughthe body of divided tobacco and into the filter; and (c) allowing thesmoke to pass through the filter thereby filtering the smoke.
 33. Aniron analog of C.I. Reactive Blue 21 dye.
 34. Paper impregnated with aniron analog of C.I. Reactive Blue 21 dye.
 35. A method of making a firsttobacco smoke filter segment, comprising the steps of: (a) providing oneor more than one copper-containing porphyrin; (b) producing a mixture ofcellulose fiber and the copper-containing porphyrin; (c) heating themixture for a sufficient time at one or more than one temperaturesufficient to covalently link the copper-containing porphyrin to thecellulose fiber; (d) rinsing the mixture of cellulose fiber withcovalently bound, copper-containing porphyrin after heating the mixture;and (e) forming the cellulose fiber with covalently bound,copper-containing porphyrin into the first tobacco smoke filter segment.36. The method of claim 35, where the copper-containing porphyrinprovided is a copper phthalocyanine.
 37. The method of claim 35, wherethe copper-containing porphyrin provided is C.I. Reactive Blue 21 dye.38. The method of claim 35, where the mixture of cellulose fiber and thecopper-containing porphyrin produced comprises a ratio of about 1.2:10copper-containing porphyrin to cellulose fiber by weight.
 39. The methodof claim 35, where the mixture of cellulose fiber and thecopper-containing porphyrin further comprises sodium sulfate andchlorine water.
 40. The method of claim 35, further comprising addingone or more than one additional substance to the cellulose fiber withcovalently bound, copper-containing porphyrin.
 41. The method of claim40, where the one or more than one additional substance is selected fromthe group consisting of activated charcoal, chitin and lignin.
 42. Themethod of claim 40, where the one or more than one additional substanceis selected from the group consisting of an antioxidant, dry water, ahumectant, microcapsules, a radical scavenger, a surfactant andcombinations of the preceding.
 43. A method of making a smokable devicecomprising the steps of: (a) providing a first tobacco smoke filtersegment made according to claim 1; and (b) affixing the first tobaccosmoke filter segment to a body of divided tobacco.
 44. The method ofclaim 43, further comprising the step of affixing a second tobacco smokefilter segment that is substantially free of copper-containing porphyrinto the body of divided tobacco.
 45. The method of claim 44, where thesecond tobacco smoke filter segment affixed to the body of dividedtobacco comprises cellulose acetate fibers treated with triacetin.
 46. Atobacco smoke filter comprising a first tobacco smoke filter segmentmade according to claim
 35. 47. A tobacco smoke filter comprising afirst tobacco smoke filter segment made according to claim 35, furthercomprising a second tobacco smoke filter segment that is substantiallyfree of copper-containing porphyrin.
 48. A smokable device comprisingthe tobacco smoke filter according to claim 46 affixed to a body ofdivided tobacco.
 49. A smokable device comprising the tobacco smokefilter according to claim 47 affixed to a body of divided tobacco.
 50. Amethod of filtering tobacco smoke comprising the steps of: (a) providingthe smokable device of claim 48; (b) igniting the body of dividedtobacco such that smoke passes through the body of divided tobacco andinto the filter; and (c) allowing the smoke to pass through the filterthereby filtering the smoke.
 51. A method of filtering tobacco smokecomprising the steps of: (a) providing the smokable device of claim 49;(b) igniting the body of divided tobacco such that smoke passes throughthe body of divided tobacco and into the filter; and (c) allowing thesmoke to pass through the filter thereby filtering the smoke.
 52. Amethod of making a smokable device comprising the steps of: (a)providing a first tobacco smoke filter segment made by; i) providing oneor more than one copper-containing porphyrin; ii) producing a mixture ofcellulose fiber and the copper-containing porphyrin; iii) heating themixture for a sufficient time at one or more than one temperaturesufficient to covalently link the copper-containing porphyrin to thecellulose fiber; and iv) forming the cellulose fiber with covalentlybound, copper-containing porphyrin into the first tobacco smoke filtersegment; (b) affixing the first tobacco smoke filter segment to a bodyof divided tobacco; and (c) affixing a second tobacco smoke filtersegment that is substantially free of copper-containing porphyrin to thebody of divided tobacco.
 53. The method of claim 52, where thecopper-containing porphyrin provided in step (a) is a copperphthalocyanine.
 54. The method of claim 52, where the copper-containingporphyrin provided in step (a) is C.I. Reactive Blue 21 dye.
 55. Themethod of claim 52, where the mixture of cellulose fiber and thecopper-containing porphyrin produced comprises a ratio of about 1.2:10copper-containing porphyrin to cellulose fiber by weight.
 56. The methodof claim 52, where the mixture of cellulose fiber and thecopper-containing porphyrin further comprises sodium sulfate andchlorine water.
 57. The method of claim 52, further comprising rinsingthe mixture of cellulose fiber with covalently bound, copper-containingporphyrin after heating the mixture.
 58. The method of claim 52, furthercomprising adding one or more than one additional substance to thecellulose fiber with covalently bound, copper-containing porphyrin. 59.The method of claim 58, where the one or more than one additionalsubstance is selected from the group consisting of activated charcoal,chitin and lignin.
 60. The method of claim 58, where the one or morethan one additional substance is selected from the group consisting ofan antioxidant, dry water, a humectant, microcapsules, a radicalscavenger, a surfactant and combinations of the preceding.
 61. Themethod of claim 52, where the second tobacco smoke filter segmentaffixed to the body of divided tobacco comprises cellulose acetatefibers treated with triacetin.
 62. A smokable device made according toclaim
 52. 63. A method of filtering tobacco smoke comprising the stepsof: (a) providing the smokable device of claim 62; (b) igniting the bodyof divided tobacco such that smoke passes through the body of dividedtobacco and into the filter; and (c) allowing the smoke to pass throughthe filter thereby filtering the smoke.
 64. A tobacco smoke filtercomprising: (a) a first tobacco smoke filter segment made by a methodcomprising the steps of: (i) providing one or more than onecopper-containing porphyrin; (ii) producing a mixture of cellulose fiberand the copper-containing porphyrin; (iii) heating the mixture for asufficient time at one or more than one temperature sufficient tocovalently link the copper-containing porphyrin to the cellulose fiber;and (iv) forming the cellulose fiber with covalently bound,copper-containing porphyrin into the first tobacco smoke filter segment;and further comprising a second tobacco smoke filter segment that issubstantially free of copper-containing porphyrin.
 65. A smokable devicecomprising the tobacco smoke filter according to claim 64 affixed to abody of divided tobacco.
 66. A method of filtering tobacco smokecomprising the steps of: (a) providing the smokable device of claim 65;(b) igniting the body of divided tobacco such that smoke passes throughthe body of divided tobacco and into the filter; and (c) allowing thesmoke to pass through the filter thereby filtering the smoke.